What if Brock Lesnar hadn't left WWE in 2004?

#1 John Cena would not have become the face of WWE

Brock Lesnar takes out John Cena on his WWE return in April 2012

Unquestionably the biggest impact from Brock Lesnar remaining in WWE in 2004 would have been the development of the man who would become the most famous wrestler in the company following Lesnar's departure, John Cena.

No-one benefitted more, long term from Lesnar leaving than Cena. At Lesnar's final event, Wrestlemania XX, Cena competed in the opening match wherein he defeated The Bigshow to win his first title in WWE, the United States Championship.

Cena competed in the mid-card throughout 2004, until he was positioned as a contender for JBL's WWE Championship at Wrestlemania 21; a match he won to claim his first of sixteen World titles.

Prior to Wrestlemania 21, there was significant debate over whether Cena would win the title or not. Leading up to the show, the likelier result appeared to be JBL retaining as WWE management felt that Cena needed more seasoning and wasn't ready for the pinnacle. However, with a dearth of main event stars, Vince McMahon in the days preceding the show, finally decided to go all the way with Cena.

Had Lesnar stayed, it's likely he would have been defending the WWE Championship at Wrestlemania versus Cena. Given that Lesnar was a far superior all round talent than Cena at that point (and for that matter, would ever be), it seems likely that McMahon would have stuck to his initial instincts and made Cena wait for his big moment.

This would likely have come at Wrestlemania 22 instead, given that the other big winner from Wrestlemania 21, Batista was injured when Wrestlemania 22 occurred.

That on its own would have seen Cena win two fewer WWE Championships and with Lesnar on the roster during Cena's entire WWE tenure, and as a more credible Champion, Cena today, would have a considerably lesser number of World title reigns on his resume. It's likely that The Rock's return in 2011 would have seen him challenge Lesnar, not Cena at Wrestlemania 28, the following year. Had Lesnar stayed, he would have been the biggest star of the modern WWE generation and Cena's current stardom and status would be more equivalent to that of Randy Orton. A big star in wrestling but not in the mainstream. Perhaps Lesnar would have married Nikki Bella too!